I've had something similar on my two fiesta's, not so much my newer one.

The only thing that could replicate it was reaching 3k rpm in 2nd or 3rd gear and a little squeak would crawl out near the drivers side wheel. Was very high pitched. Did this on flat roads, cobbles (Don't try this) straight roads, bendy roads etc. sometimes it did it, sometimes it didn't.

Just got very annoying thinking that something was wrong, Ford checked, nothing, another garage checked, nothing.

After numerous attempts to tell the woman behind me she was up my ****, (Brake testing, going over the speed limit to get away from her, 40 in a 30, gesturing for her to overtake me which she blindly ignored) I went round a roundabout and she was about touching my bumper, so I went ahead, checked there wasn't much traffic, slowed to a stop and stuck the hazards on.

When I got out the car she looked at me as if I was an alien, I asked why she was so close to me and why she didn't get the message, she through her hands up in the air and said "I don't know"...

A white van driver behind was shouting the usual abuse... but at her..

Either way she still followed me but stayed a good 10 metres away.

The thing that ticked me off is that she did this for 10 minutes... When I sped up she did aswell, she closed any gap that I made and then she said she didn't know why?!?!?!

I took it to Ford and they couldn't recreate it, so I sat there and did it myself and it made a disgusting noise.

They took another look at it, said they couldn't find anything out of the ordinary but they must of done something because if it ever did make a noise it was a lot shorter and quieter, and it did it less often. Strange.